Heat is what actually ages your electronics

This looks at thermal ageing from the practical end — what holds up once conditions stop being ideal.

Chemistry speeds up with temperature

Most degradation processes are chemical reactions, and reaction rates rise steeply with temperature in a well-established relationship. A common rule of thumb in reliability engineering is that a rise of roughly ten degrees Celsius can halve the life of a temperature-sensitive component.

The exact factor depends on the material and the failure mechanism, so the rule is an approximation rather than a law. The direction and the steepness, however, are not in dispute for any of the components in a typical device.

Batteries lose capacity permanently

Side reactions at the electrode surfaces consume lithium and thicken the passivating layer, both of which reduce capacity irreversibly. These reactions proceed whether or not the cell is in use, and they accelerate sharply with temperature and with state of charge. This is why a phone left in a hot car at full charge suffers more in a day than in a month of normal use.

Cooling a battery is more valuable than any charging habit if you have to choose.

Capacitors dry out

Electrolytic capacitors lose electrolyte through their seals over time, and the rate depends strongly on temperature. As they dry, their capacitance falls and their internal resistance rises, which is why power supplies fail before the circuits they feed. Bulging or leaking capacitors near heat sources are one of the most common repairable faults in consumer electronics.

In practice, a device with its capacitors sited next to a hot component will fail there first, and that is a design decision.

Mechanical stress from cycling

Materials expand at different rates, so every heating and cooling cycle stresses the joints between them. Repeated cycling propagates cracks in solder joints and in the interfaces inside chips, a mechanism known as thermal fatigue. This is why devices that run hot and are frequently switched on and off suffer more than those left running warm.

It is also why reflow repairs sometimes revive a device temporarily and rarely fix it permanently.

Thermal interface material degrades

The paste between a processor and its heatsink dries and separates over years, raising thermal resistance across the joint. The symptom is a machine that throttles at loads it used to handle, with no other change. Replacing it is inexpensive and restores the original path, provided the heatsink is also clean.

In practice, pads and pastes vary in longevity, and the cheap material used in some devices is a genuine limiting factor.

What to actually do

Keep intake and exhaust vents clear, and clean dust from fins annually in dusty environments. Avoid stacking equipment, blocking vents with furniture, or leaving devices in direct sun and closed cars. For anything running continuously, ambient room temperature is a lever worth a surprising amount of lifespan.

Where a device offers a quieter or cooler mode, the cooler mode is the one that lasts longer.

The takeaway

Every degree you remove buys time. Dust and blocked vents are where most of it is lost.

The constraint is almost always physical, and marketing rarely mentions which one.